Core: Display build cpu architecture in about dialog

Previously we were displaying the word size: 32 bit, 64 bit, but
nowadays we could have x86_64 and arm64 and "64 bit" doesn't cut
it anymore.

Change-Id: I02c1942eae2b93726554561fa4eb83ac8a97dfa0
Reviewed-by: <github-actions-qt-creator@cristianadam.eu>
Reviewed-by: Alessandro Portale <alessandro.portale@qt.io>

src/plugins/coreplugin/icore.cpp

@@ -647,9 +647,9 @@ QString ICore::versionString()
 */
 QString ICore::buildCompatibilityString()
 {
-    return tr("Based on Qt %1 (%2, %3 bit)").arg(QLatin1String(qVersion()),
+    return tr("Based on Qt %1 (%2, %3)").arg(QLatin1String(qVersion()),
                                                  compilerString(),
-                                                 QString::number(QSysInfo::WordSize));
+                                                 QSysInfo::buildCpuArchitecture());
 }
 
 /*!